Hi Jane
We are in a similar situation. We received post with just our address on it recently, and upon opening it saw it was an invoice for a large purchase. It had been paid by someone whose name we didn't recognise as a past inhabitant of our house.
Anyway, we called the company today and they confirmed that the package was delivered to our address to this person whose credit card (Lloyd's) is also registered to our address. I don't know how this happened, as we didn't take delivery, so this guy must have hung around on the appointed day & convinced the delivery people to give him the package??? I can't even manage to get a genuine delivery to arrive on time, so this must be one committed individual.
Anyway, my husband is going to Lloyd's tomorrrow to try to figure this out - if you work out what's going on, please let me know, either here or by PM. Good luck!